Persuasion via Social Norms: A (Non)Polluting Engine for Environmental Action Robert B. Cialdini, Regents' Professor Emeritus, Departments of Psychology and of Marketing, Arizona State University Social norms are remarkably powerful in directing human action. Communications that use social norms-based appeals for environmental action have proven significantly more persuasive than those that use traditional appeals. But, this motivating power is often used incorrectly or even counterproductively. Cialdini explains how to avoid THE BIG MISTAKE of social norms messaging and how, instead, to maximize its positive impact. Elected in 2019, Cialdini represents the Academy's section on Psychological and Cognitive Sciences.